Using zcs-7.1.1_GA_3196.UBUNTU10_64.20110527011124 as a mail filter to an exchange box, using ZimbraMailTransport. All was working fine until this morning when the zimbra box received a bad dns request from one of the windows dns servers and decided that the internal exchange MTA wasn't accessible. Since then all incoming mail was unable to relay to the exchange box and bounced. I've since changed dns on the zimbra box to have it's own local zone rather than forward internal lookups to the main windows dns - it performs it's own external lookups. So it's now self contained.
Question is, have all the messages over the 2 hour period before the issue was raised gone? I've not changed the standard postfix config so is there any chance that mail delivery will be attempted? Nothing is showing in the zimbra backend as deferred.